This invention generally relates to an image forming apparatus and, more particularly, to an image forming apparatus with a color change area discriminating function, for example, suitable for an electric copying machine.
It is known that copying machines have functions for copying an original image in an equal-, reduced-, or enlarged-size mode. In recent years, various types of copying machines have been developed and used in practice. For example, in one conventional copying machine, an image within a predetermined area of an original is erased or copied in a color different from that of an image outside the predetermined area. In another conventional copying machine, an image outside a predetermined area is simply erased or copied in a color different from that of the image within the area.
An erasure or color change area is designated by a separate key excluded from normal operation keys for image formation. For this reason, it is difficult for an operator to understand an area of interest subjected to erasure or color change designation.
U.S. application Ser. No. 825,876 entitled "Image Forming Apparatus With Area Selection And Preservation Functions" and filed on Feb. 4, 1986 by the same assignee with the present application and allowed on Sep. 29, 1986 by the UNITED STATES DEPARTMENT OF COMMERCE Patent and Trademark Office describes an arrangement having a display unit for allowing easy discrimination of the erasure area. However, it is still difficult to immediately discriminate the color change area by the above-noted arrangement.